1. Field of the Invention
The present invention is broadly directed to cable and wire bundle clamps. More specifically, the present invention is directed to avionic cable or wire bundle clamp assemblies which require no tools for fastening the clamp about a cable or bundle of wire.
2. Brief Description of the Prior Art
Wire bundle clamps, hose clamps and the like have been known in the prior art for a long time.
Most wire bundle and hose clamps of the prior art have an elongated strap which is designed to be disposed around the wire bundle, hose, or other object to be gripped, and a fastener or strap receiving member. The fastener or strap receiving member is usually permanently attached to one end of the strap. The other end of the strap is passed through an opening in the strap receiving member and is movably attached thereto by the use of a worm or like screw. The size of the opening or loop of the strap is then adjusted, i.e., the object is then gripped by turning of the worm or screw with a suitable tool such as a screwdriver or wrench. Examples of wire bundle or hose clamps of the above noted type are found in U.S. Pat. Nos. 4,021,892, 3,914,832, 4,047,268, 3,924,308, 4,103,637, and 4,099,304; and in British patent specification Nos. 1,500,073 and 363,973.
Another basic type of wire bundle clamp requires no tools for adjustment of the length of the looped strap around the object to be gripped. Wire bundle clamps of this type are typically made as one-piece, integrally constructed devices, and include a strap and a head or housing integrally molded with the strap. The head or housing includes a strap receiving slot, and an integrally molded pawl. Both the strap and the pawl are provided with appropriately positioned teeth or serrations. The pawl is configured to snap into locking position within the slot and to engage and permanently lock the strap therein. Wirebundle clamps of this, or similar type, are described in U.S. Pat. Nos. 3,127,648, 3,900,922, 2,936,980, 3,537,146, and 3,660,869.
Additional disclosures generally relating to the subject of wire bundle or hose clamps, or bands or straps of adjustable length for gripping objects are found in U.S. Pat. Nos. 3,214,808 and 3,570,497 and in British patent specification Nos. 1,013,500 and 1,006,129.
As is well appreciated by those skilled in the art, cable, wire bundle, or hose clamps and the like utilized in the relatively hostile environment of an aircraft should ideally meet special, strict requirements. Briefly, in an aircraft environment, numerous cables and wire bundles are assembled to special racks in very limited space. Because of the critical importance of certain electric and electronic circuits in civilian and military aircraft for flight safety and ability for effective combat, inadvertent overtightening of the clamps must be avoided in order to eliminate damage to the cables. Moreover, the cable or wire bundle clamps of an aircraft are often subjected to extreme temperatures, such as heat emanating from an engine, or the freezing cold of the ambient atmosphere surrounding an aircraft flying at high altitudes. In addition, cable or wire bundle clamps utilized in an aircraft must be essentially failproof, even under exposure to constant and severe vibration, and yet adapted for easy and quick disassembly for servicing of the electric and electronic components.
In an effort to fill the need in the prior art for cable, wire bundle and hose clamps adapted for use in aircrafts, a clamp was developed which, inter alia, intrinsically limits the amount of force utilizable by a mechanic who tightens the clamp. This clamp is described in U.S. Pat. No. 4,303,216, assigned to the same assignee as the present application.
The clamp described in U.S. Pat. No. 4,303,216 is, however, of the worm or screw-tightened type. Therefore, a tool such as a screwdriver or wrench is still required to tighten the clamp around a cable or wire bundle. On the other hand, cable or wire bundle clamps of the prior art, which require no tool for tightening, are not generally well adapted for use in an aircraft environment. A principal disadvantage of the prior art clamps described in the U.S. Pat. Nos. 3,127,648, 3,900,922, 2,936,980, 3,537,146, and 3,660,869 is that these cable clamps, once tightened, are not readily disassembled. For example, U.S. Pat. No. 3,537,146 specifically states that after tightening, the excess of the strap protruding above the strap receiving housing may even be cut off. This further demonstrates that the cable tie of that patent is primarily designed for one-time use only.
Accordingly, the present invention is designed to fill the need in the prior art for a cable or wire bundle clamp which generally meets the requirement of an aircraft environment and which can be tightened, released and reused without the application of tools.